in] MOUTH-PARTS AND SENSE-ORGANS 43 



flea then lifts its abdomen upwards and presses the 

 piercing organs down into the skin. In doing this, 

 it uses its own weight and the strength of the fore- 



Fig. 4. Diagram of the mouth-parts of a flea. The slender 

 awl-like structure at the top is the labrum. Beneath 

 are the paired mandibles with serrated edges. The 

 four-jointed hairy maxillary palpus is below, only one 

 being shown. Protruding from the base of the face is 

 the Idbium which supports the jointed labial palpi. The 

 flat obtuse triangular structure from which the palpus 

 springs is the right-hand maxilla. The left maxilla is 

 concealed behind. 



most and middle pairs of legs. The hind pair of legs 

 are lifted up into the air. The head can soon be 

 seen coming nearer the skin. The rostrum then 



